Before 1919, most scientists held that the universe was only as large as ...
Before 1919, most scientists held that the universe was only as large as the Milky Way and that it was a constant size. Then, in 1919, the American astronomer Edwin Hubble — aided by a technologically advanced 100-inch telescope — was able to discern individual stars within what he believed to be a nebula, a fuzzy cloud of light composed of cosmic gases. After calculating that the distance to these stars from Earth was much further than the known reaches of the Milky Way, he concluded that the stars were part of a galaxy separate from our own. The idea that our galaxy was just one of many galaxies changed forever the way we view our place in the universe.